Football fans can best judge the game-day merits of the reinvented Memorial Stadium at UC Berkeley, site of Saturday's 115th showdown between Stanford and Cal.

But you don't need a ticket to explore the stadium's setting and see the merits of treating landscape and architecture as inseparable from the start.

The slope leading up from Piedmont Avenue is less ragged than before, with inviting paths running through aged redwoods and oaks. The stadium's curve of arches retains its stony grandeur, a classical relic in a 21st century terrain of broad plazas and event-scaled staircases.

A sci-fi look

Topping all this, literally, a silvery press box looks as though it flew in from a sci-fi flick to perch upon the arches facing the bay, a startling sight that somehow fits right in.

This is an extension of Cal's central campus that succeeds at feeling collegiate and rugged at once. It also has a lesson that can be applied elsewhere: When institutions or developers take on large projects in delicate settings, don't be timid about blending old and new.

The transformation is especially impressive given the long battle over the $470 million complex, which straddles the Hayward Fault and includes a 140,000-square-foot student athletic center as well as a 63,000-seat stadium from 1923 that was designed by legendary Bay Area architect John Galen Howard.

Neighbors and the city of Berkeley filed lawsuits in 2006 to have the athletic center built elsewhere, citing traffic and seismic concerns. A more novel challenge came from tree-sitters who held an unsuccessful 649-day vigil to prevent 41 trees on the site - nearly all of them planted when the stadium was built - from being cut down.

The attacks delayed construction for nearly two years but did not derail the project. Nor did they weaken the strength of the design by the team of HNTB, Studios Architecture and Olin Partnership.

In addition to placing new seating and service areas within the historic arched walls, with a full seismic upgrade, the complex treats the athletic center as part of the landscape. The roof doubles as the concourse plaza while the west-facing wall is clad in stone, less a structure than a form that carries the curve of the stadium down toward the central campus.

Good landscaping mix

The mature trees that remained on the site are joined by more than twice as many new ones and such forest-friendly groundcovers as rosemary and sword ferns. The outer edge of the concourse plaza has grassy areas and a line of elms as well.

The intent was not to pretend that nothing had changed. One paved path runs alongside the athletic center wall; the statuesque trees on the west are countered by a wall of stacked limestone, with 18-inch-deep horizontal slits that allow light to slice down upon the athletes training below. The two staircases leading to the concourse are broad arcs meant to announce their presence.

"The notion was to minimize the amount of impact on the existing landscape while extending the connections through the site," said David Rubin, who led the landscape design effort at Olin and now heads the firm Land Collective.

As for the press box, it's the most futuristic work of architecture in a city that often is resistant to change.

The football-field-length structure of glass and white steel rests on a concrete foundation at the top of the stands, but the most visible support is a series of thin, sharply diagonal trusses.

If the upper two levels had a heavier look, or extended the full length of the stadium wall, the effect would be ruinous to Howard's curved bowl. Instead, HNTB and Studios pulled off a remarkable balancing act. The contrast in materials and style makes the addition seem to hover atop the arched landmark while leaving the latter's visual integrity intact.

That's no simple feat. Give the landscape time to mature, and in another decade visitors are likely to wonder what the long-ago fuss was all about.